The present day telephone system provides a way for its subscribers to verbally communicate with one another. The verbal communications must occur in real time and require that the sender and recipient have simultaneous access to their telephone stations for communication. If the sender is unable to initially place the call at a time when the recipient has access to his telephone, the sender must continue to repeat the call until the recipient is present. Similarly, if the sender desires to send the same verbal message to a number of recipients, he must repeat this process of establishing telephone contact with each recipient and repeating the message. Thus, the present day method of delivering verbal communications is time consuming, and in the business community the time spent in such present day verbal communications is inefficient and reduces personal productivity.
While auxiliary devices, such as telephone recording systems, may be installed for individual telephone sets, such devices do not fill the need for the rapid and efficient delivery of verbal messages in the business community. A need has thus arisen for a centralized telecommunications system which eliminates many of the inconveniences, efficiencies and time consuming requirements of the existing telephone network.
One solution to this problem has been the very recently developed voice message system that receives audio messages from telephone stations for storage and later retrieval by another party. A memory means controlled by an electronic digital signal processing means stores deposited verbal messages along with the telephone station addresses of the message recipients. A communications system then automatically takes over the function of delivering the messages to the addresses. A user can also access the system to inquire and receive any stored messages addressed to him.
Security in such voice message systems has been provided in that the system may require the user to enter an authorization code which is checked for validity prior to access to the message deposit function of the system. In addition, the user inquiring about messages or receiving notification from the system of a message to be delivered may be required to enter a unique authorization number which is validated by the system prior to message delivery.
While the I.D. checking by comparison of phoned-in digits with stored digital representations of valid authorization codes may generally provide an adequate level of security for satisfying the system with the user's authorization, there are special circumstances demanding a still higher security level. One such case may involve corporate subscribers whose office management users typically deposit messages of a sensitive business nature in the system for delivery to authorized recipients only. In that case, special measures would be advisable to defeat computer pirates, including professionals utilizing very sophisticated high speed number generators, amateurs, and so-called "computer hacks", utilizing endless patience at the keyboard of a small personal computer.